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target/i386: do not set unsupported VMX secondary execution controls
Commit 048c951 ("target/i386: work around KVM_GET_MSRS bug for secondary execution controls") added a workaround for KVM pre-dating commit 6defc591846d ("KVM: nVMX: include conditional controls in /dev/kvm KVM_GET_MSRS") which wasn't setting certain available controls. The workaround uses generic CPUID feature bits to set missing VMX controls. It was found that in some cases it is possible to observe hosts which have certain CPUID features but lack the corresponding VMX control. In particular, it was reported that Azure VMs have RDSEED but lack VMX_SECONDARY_EXEC_RDSEED_EXITING; attempts to enable this feature bit result in QEMU abort. Resolve the issue but not applying the workaround when we don't have to. As there is no good way to find out if KVM has the fix itself, use 95c5c7c77c ("KVM: nVMX: list VMX MSRs in KVM_GET_MSR_INDEX_LIST") instead as these [are supposed to] come together. Fixes: 048c951 ("target/i386: work around KVM_GET_MSRS bug for secondary execution controls") Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20200331162752.1209928-1-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> (cherry picked from commit 4a910e1) Conflicts: target/i386/kvm.c *drop context dep. on 6702514 Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
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